Running head: Raccoons and exotic felids1

Zoonoses of Procyonids and Non-Domestic Felids2

Edward C. Ramsay, DVM, DACZM3

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KEYWORDS5

Baylisascaris procyonis, Non-domestic felid, Procyonid, Procyonis lotor, Raccoon, Zoonosis6

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Department of Small Animal Clinical Sciences, College of Veterinary Medicine, The University of9

Tennessee, Knoxville, TN 37996, USA10

E-mail address: eramsay@utk.edu11

[Introduction]12

Relatively few species in the Order Carnivora, other than domestic dogs, cats, and ferrets, are13

kept as pets, but members of the Families Procyonidae and Felidae are the most likely non-14

domestic carnivores to be kept by private owners. Additionally, many non-domestic felids and15

procyonids are exhibited by zoos and native wildlife parks. In the wild, contact with non-16

domestic felids is rare but wild raccoons are common throughout North American, and17

frequently found near human dwellings and parks.18

Reports of zoonoses transmitted from procyonids and non-domestic felids are19

uncommon, with a few notable exceptions. As with any zoonosis, immuno-compromised20

individuals and children are at the greatest risk of acquiring zoonoses and particular care must21

be made to avoid infections in these people.22

PROCYONIDS23

The Family Procyonidae contains small to medium-sized omnivores that live in the temperate24

and tropical regions of the Western Hemisphere. The best-known member of this group is the25

common raccoon, Procyon lotor, which lives throughout North America, and has feral26

populations established in Japan and Europe. Other species of procyonids live in the West27

Indies, and Central and South America. The coatimundi, Nasua nasua, is similar in size to the28

raccoon and ranges from Arizona to Argentina. The kinkajou, Potto flavus, and the olingos,29

Bassaricyon spp., are smaller, mostly arboreal procyonids of Central and South America. This30

family also includes the rarely seen ring-tailed cats, Bassariscus spp., from western North and31

Central America.32

Raccoons are the most common privately-owned procyonid seen in our practice and33

popular exhibit animals worldwide. Wild raccoons live in urban, suburban, and rural areas and34

are well adapted to living in close proximity to people. Raccoons will feed on garbage, and also35

use bird feeders and unattended pet food as food sources. Increased interactions with36

raccoons are likely as human populations continue to expand. It is estimated that the raccoon37

population of the US will double over the next 10 years.1 Kinkajous are prehensile-tailed38

procyonids and occasionally kept as pets. Other procyonids are rarely kept in the US but may39

be kept as pets within their range countries. The discussion of zoonoses in this section will40

refer almost strictly to raccoons, alluding to kinkajous where data is available.41

Raccoons are susceptible to most zoonotic diseases which infect domestic dogs.42

Serological surveys have also identified wild raccoons infected with a number of less common43

zoonotic agents, including Bartonella rochalimaea,2 Francisella tularensis,3 influenza virus,444

Trichenella spiralis,5 and Trypanosoma cruzi.6 Of minor zoonotic pathogens, Ehrlichia chaffeenis45

is probably the only organism for which raccoons are a potential reservoir host.746

Remarkably, there are very few reports of humans acquiring infections from raccoons,47

with the exceptions of two pathogens: rabies, and the ascarid, Baylisascaris procyonis. Rabies is48

endemic in raccoons in the eastern portion of the US and is discussed in another chapter in this49

book.50

Baylisascaris procyonis51

Baylisascaris procyonis is an enteric nematode parasite of raccoons (Figure 1) and has recently52

been found in a pet kinkajou (A. Greene, personal communication). Domestic dogs have also53

been found to shed B. procyonis ova.8 B. procyonis ova are very hardy and can remain infective54

in the environment for a long time; making exposure possible long after raccoons are gone.55

Reported infection prevalence rates in raccoons range up to 85%, with the western, upper56

Midwest and northeastern parts of the US having the greatest reported prevalences.9 B.57

procyonis can have a direct life cycle, but raccoons are most likely to acquire this organism via58

ingestion of an intermediate host, such as an infected rodent. Raccoon infections are typically59

asymptomatic but younger animals have heavier parasite infections and may show clinical60

signs. Infected raccoons may pass thousands of B. procyonis ova.10 Diagnosis of infection in61

procyonids is by identification of characteristic ova on fecal flotation exam or by direct62

observation of the adult worms at necropsy.63

People acquire B. procyonis by ingestion of infective ova. Individuals with a propensity64

to eating dirt or soil (geophagia), such as very young children or mentally handicapped65

individuals are at greatest risk for infection. Most human infections appear to be66

asymptomatic.11 Severe clinical presentations are the result of visceral, ocular, or neural larval67

migrans. Visceral larval migration may affect the heart, lungs, intestines, or mesenteries.68

Ocular larval migration may cause choroidioretinitis or optic neuritis and may result in visual69

defects or even blindness.12,13 Fewer than 20 cases of neural larval migrans have been reported70

in North American but most of those cases have resulted in death or persistent, severe71

neurological deficits. All reports of neural larval migrans have been in males, and either were72

children or mentally-challenged individuals. Treatment of exposed individuals before the onset73

of clinical signs with albendazole may be useful.1074

There are several strategies for preventing human infection with Baylisasarcis procyonis.75

Avoiding raccoon latrines and contact with raccoon feces or contaminated areas are the most76

straight forward methods to avoid infection Young children and others at increased risk of77

ingesting ova should be supervised when outside in areas with high raccoon activity. People78

should not intentionally feed wild raccoons and avoid practices which attract raccoons, such as79

leaving human and pet food outdoors overnight. Garbage containers should have tight lids and80

remain sealed overnight. Sealing off or raccoon-proofing areas, such as garages and81

unattended barns, may prevent the development of raccoon latrines near homes. Removal of82

raccoon latrines, and treatment of potential intermediate rodent hosts is another strategy for83

reducing the risk of infection in people.1484

NON-DOMESTIC FELIDS85

The Family Felidae contains approximately three dozen species, which are native to all86

continents except Australia. The genus Panthera contains the charismatic large cats: lions (P.87

leo); tigers (P. tigris); leopards (P. pardus & P. uncia); and jaguars (P. onca). The cheetah88

(Acinonyx jubatus) is a distinctive felid and the only member of its genus. The taxonomy of the89

remainder of the felids is under seemingly continuous debate but some have included all these90

smaller cats in a single genus, Felis. All felids are strict carnivores.91

Non-domestic felids are not recommended as pets, but several species can be legally92

acquired and are occasionally kept by private individuals. Two small, attractive American felids,93

the ocelot (Felis pardalis) and margay (F. wiedii), were once popular but are now seldom seen94

as pets. Servals (F. serval), caracals (F. caracal), and mountain lions (also known as the cougars95

or puma, F. concolor) are the most commonly seen privately-owned non-domestic felids in our96

practice.97

All non-domestic felids appear to be susceptible to diseases commonly infecting98

domestic cats. As such, any zoonosis which might be acquired from domestic cats could99

potentially be acquired from non-domestic felids. Very few zoonoses, however, have been100

documented to be contracted from a non-domestic felid. Two groups of pathogens,101

dermatophytes and enteric organisms, deserve mention as risks when working with exotic102

felids. Of the latter, knowledge of the biology of Toxoplasma gondii is frequently required for103

counseling owners of exotic felids and animal keepers.104

DERMATOPHYTOSIS105

Microsporum canis is a keratophilic fungus which causes superficial skin infections in domestic106

cats and dogs and has been the dermatophyte most commonly associated with disease in107

exotic felids. Dermatophytosis in exotic cats is similar to the disease in domestic cats, and108

lesions can include papular and miliary dermatitis or areas of alopecia on the face, body, and109

limbs.15 Inapparent carriers may also exist. Diagnosis is made by clinical signs and fungal110

culture of lesions.111

In most cases, infections appear to be self-limiting. Treatment may be attempted for112

severe or complicated cases, however, in one study of topical treatments of tigers and their113

outdoor exhibits, untreated (control group) animals resolved infections as fast as or faster than114

any treated tigers.15 Focal lesions on kittens can be clipped, cleaned with a tamed iodine115

solution, such as povidone iodine, and treated with topical antifungal agents, such as116

miconazole or clotrimazole. Systemic treatment with oral itraconazole will speed resolution of117

lesions in adult cats (E. Ramsay, personal experience). Griseofulvin toxicity causing bone118

marrow depression and death has been reported in cheetahs.16119

Dermatophytosis in people is characterized as focal, circular skin lesions (Figure 2), but120

lesions may also include alopecia. Inflammation may be minimal to intense, with vesicles121

and/or scaling present. The lesions can be pruritic. Diagnosis is based on history of exposure to122

infected animals, clinical signs, and fungal cultures. Physicians should be consulted regarding123

treatment. Wearing protective clothing and gloves and otherwise avoiding direct contact with124

infected cats is advised. Frequent handwashing following contact with infected felids also125

appears to limit zoonotic infections.126

ENTERIC PATHOGENS127

Toxocara cati and hookworms, Ancyclostoma spp., are common zoonotic parasites of domestic128

cats and have been found in several species of non-domestic felids.17 T. cati infections rarely129

cause clinical signs in exotic felids but can be persistent, despite aggressive anthelminthic130

treatment. Infectious ascarid ova can be sequestered in an exhibit’s crevices or substrate and131

remain infective for months to years, even in the most diligently cleaned enclosures.132

T. cati and hookworms can cause visceral and cutaneous larval migrans, respectively, in133

people. Human infections with T. cati are acquired through ingestion of infective ova.134

Hookworm infections most typically occur when free-living larvae penetrate the skin. Both135

infections are more common in individuals who might consume contaminated soil or have136

considerable exposure to contaminated earth, such as children. A number of common137

anthelminthics are used to treat human infections.138

Non-domestic cats fed raw meat diets can commonly be asymptomatic carriers of139

Salmonella spp.18 Diets are presumed to be the source of the bacteria, but cultures of food140

items do not always reveal the same organisms cultured from feces. Salmonellosis may occur141

in felids, but more frequently they shed Salmonella spp. without showing clinical signs.142

Providing diets with low bacterial contamination, such as by acquiring meat from processors143

with human food quality hygiene practices, will limit shedding of Salmonella spp. in non-144

domestic felids.19145

Gastrointestinal signs, such as vomiting and diarrhea, are the most common clinical146

presentations associated with salmonella infections in people. Systemic signs are seen in147

severe infections. No reports could be found of human salmonellosis acquired from an exotic148

felid149

Serologic surveys of our collections have shown non-domestic felids to be commonly150

infected with Toxoplasma gondii. Domestic cats are known to be the definitive host for this151

organism, and it is assumed that all felids may act as definitive hosts. While no records of152

transmission of T. gondii from exotic felids to humans could be found, veterinarians are153

frequently called upon to council private owners, animal caretakers, and zoological collection154

managers about the risks of people becoming infected, especially when owners or keepers are155

pregnant.156

Cats recently infected with Toxoplasma gondii shed the organism in feces for two to157

three weeks. Oocysts require at least 24 hours outside the body to sporulate and become158

infective. Transmission to people occurs following consumption of infective oocysts. The vast159

majority of human toxoplasmosis infections cause few signs or only mild flu-like disease, and160

are not diagnosed. In immunocompromised individuals, severe clinical disease including161

encephalitis may occur. Infection during pregnancy may result in fetal infection and cause fetal162

death or miscarriage. In utero toxoplasmosis can cause fetal chorioretinitis and result in163

blindness of the neonate.164

Avoiding contact with cat feces is the primary method to avoid infection with all enteric165

pathogens. Frequent hand washing and not eating, drinking, or smoking while feeding felids or166

cleaning enclosures will limit an individual’s exposure to these pathogens. Wearing gloves167

when cleaning cat boxes or enclosures, and digging in soils contaminated with cat feces is also168

recommended. Hookworm infections can be avoided by wearing shoes in areas contaminated169

with cat feces. Animal keepers feeding felids raw meat should wear gloves when handling170

diets.171

BITES172

As with any wild animal, care must be taken when dealing with procyonids and non-domestic173

felids to avoid injury to the owner, technicians, and the veterinarian. Heavy leather gloves can174

be used to restrain smaller procyonids but many can still bite through gloves. Even those175

animals most accustomed to captivity should be anesthetized or chemically restrained for176

physical examination and collection of biological samples. Procyonids and small felids can be177

netted and hand-injected with anesthetic agents. Alternately, we frequently leave the animal178

in its transport container and place the entire container in a plastic bag, creating a type of179

anesthetic chamber. The bag is filled with inhalation anesthetic gases, such as isoflurane in180

oxygen, and the animal induced without needing to be handled. Larger felids typically require181

darting.182

CONCLUSIONS183

There are very few reports of zoonotic diseases having been acquired from procyonids and non-184

domestic felids. Baylisascaris procyonis is the most commonly documented zoonotic agent in185

these taxa. Routine personal protective strategies, such as wearing gloves and avoiding contact186

with contaminated environments, remain the best strategies for preventing zoonotic infections187

from procyonids and non-domestic felids.188

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Figure legends239

Figure 1. Ova (inset) and adult Baylisascaris procyonis from a raccoon. Courtesy of The240

University of Tennessee, College of Veterinary Medicine’s Parasitology Laboratory.241

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Figure 2. The arm of a veterinarian infected with Microsporum canis, acquired from a tiger245

(Panthera tigris). Courtesy of Dr. Edward Ramsay.246

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